Aartifactual inferior wall defects of perfusion are a source of frequent concern during TI-201 exercise stress redistribution SPECT imaging in the supine position. These artifactual changes also affect Tc-99m sestamibi dipyridamole myocardial perfusion studies with supine SPECT yielding a specificity of only 58% for right coronary artery (RCA) disease. Complementary SPECT prone imaging will enhance this specificity for inferior wall abnormalities to 79% (P < 0.05) and is recommended for more accurate assessment of RCA stenosis, whether the patient challenge is pharmacological or by exercise.